"Here's the pic of the girl who got detained by police for writing on the ground with chalk."

Nancy Casanova via Twitter

Occupy L.A.'s plan last night was to use the popular Downtown L.A. Art Walk as a stage for their own "Chalk Walk" -- the most high-profile demonstration so far in their ongoing crusade to prove chalking is a Constitutional right.

Although much chalking was accomplished (messages ranged from "arrest corrupt bankers not chalkers" to the blunt "FUCK LAPD"), it soon gave way to a larger conflict:

By the end of the night, according to LAPD media-relations officer Bruce Borihanh, 17 had been arrested: One for felony vandalism, nine for misdemeanor vandalism (chalking, presumably), two for failure to disperse, three for "assault with a deadly weapon" on a police officer, one for attempted assault with a deadly weapon on a police officer, two for resisting arrest and two for "pedestrian in the roadway."

Four officers were injured in the clash, which lasted until about 11:30 p.m.

One of them, a lady cop, was "hit in the front of her face shield with one of those heavy bottles," says Borihanh. She suffered a minor concussion and will have to stay home for a couple days. The other three injured officers were male: The first came away with "bumps and scratches from a fight with one of the suspects," the second suffered "a bump on his arm from an object being thrown" and the third was badly bruised on both arms.

As usual, the LAPD's version of events differs greatly from occupiers'. This photo of Art Walk and Chalk Walk attendees stung with rubber bullets was just posted to the Occupy Los Angeles Facebook page:

"Keep your children close - especially if they like playing hopscotch."

Occupy Los Angeles

The LAPD does acknowledge that rubber bullets were used to keep order, and Borihanh says officers also swatted their batons at anyone who attempted to cross the skirmish line.

Occupy claims the clash was a result of "poor leadership" on the part of LAPD Captain Horace Frank, and writes that "the approximately 500 people who clashed with LAPD were private, regular Angelenos who are also sick & tired of the stupid and repressive tactics the LAPD employs every single day in the neighborhoods of LA."

But some Art Walk regulars have been growing tired of Occupy's presence downtown. Today, on the monthly event's Facebook page, artist Sylvia Fuller comments: "I love street art but when it comes to being peaceful and respecting property and the wishes of others, being peaceful should be the ruling outcome! I am ashamed that artists would create disunity and disrupt the events of other artists!!!"

Update, 1:15 p.m.: Here's a street-level video of the confrontation.

The uploader, nicchakim, writes that "a few protesters were yelling in the faces of the cops... but one was holding up his bike as a shield and then someone behind him threw a water bottle. The police then advanced forcing a scattered crowd to run back. The protester with his bike got knocked down and I saw the LAPD club him several times."